This decision comes after they considered signing Emi Martinez from Aston Villa, but their priority has shifted to other areas for improvement.
Onana, 29, had a difficult season with Manchester United, making several mistakes that affected the team's performance in the Premier League.
Despite this, Ruben Amorim, the team's manager, believes that Onana still has potential and wants to work with him to improve the team's goalkeeping skills.